<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<style>
		.box{
			width: 300px;
			height: 300px;
			/*background-color: black;*/
			box-shadow: inset 0 0 0 2px;
			position: absolute;
			left: 20%;
			top: 10%;
			overflow: hidden;
		}
		.change{
			width:296px;
			height: 600px;
			background-color:white;
			transform: rotateZ(45deg);
			position: absolute;
			top: -150px;
    		left: -2px;
			
		}
	</style>
	<body>
		
		<div class="box">
			
			<div class="change"></div>
			
		</div>
	</body>
</html>
